This invention relates to drill stem testing in oil and gas exploration which employ apparatus for placing instruments in a deep well bore in the earth for measuring parameters such as temperature and pressure.
It has been found that monitoring parameters such as temperature, pressure and flow rate provide useful information related to the type of material being drilled, drill bit wear, and presence of oil, natural gas or water in or adjacent the bore. Monitoring the above-mentioned parameters and characteristics of a well bore is generally referred to in the art as drill stem testing.
A difficulty associated with well logging is the requirement of removing the drill string to mount sensors thereto and then reinserting the drill string into the well bore. If more than one or two parameters are to be monitored, the problem is particularly exacerbated by the necessity of several removals and reinsertions of the drill string.
Apparatus used to introduce measuring and test instruments into well bores are known as bundle carriers. It would be desirable to use a bundle carrier which could simultaneously introduce a plurality of instruments into a well bore thereby minimizing the repetitive insertion and removal of the drill string. The bundle carrier is generally inserted into a drill string above the drill bit if simultaneous drilling and logging are to occur.
An especially difficult problem in well borehole logging is encountered in mounting instrument bundles to the exterior of a bundle carrier. The bundles and the mounting devices are exposed to the same environment as the exterior of the drill string, and must, therefore, have sufficient structural strength to prevent inadvertent removal and damage to the instruments during drilling operations. Previous instrument bundle carriers do not provide means for readily removing and replacing the instrument bundles in the field and are, therefore, inconvenient for use in many applications. Some previous bundle carriers have passages therein including sharply angled bends so that insertion of other instruments and equipment through such bundle carriers is very difficult and often impossible.